feat(notify): 站内通知补齐完成、到期逾期与知识事件

android/app/src/main/java/com/dadao/task/MainActivity.kt

@@ -36,6 +36,7 @@ import com.dadao.task.ui.TicketsScreen
 import com.dadao.task.ui.UpdateDialog
 import com.dadao.task.ui.WorkspaceScaffold
 import com.dadao.task.ui.WorkspaceTab
+import kotlinx.coroutines.delay
 
 class MainActivity : ComponentActivity() {
 
@@ -114,10 +115,14 @@ private fun AppRoot(joinUri: String?) {
             .onFailure { pendingJoin = null }
     }
 
-    // 未读数：进工作区、切页面、或通知页标了已读（unreadRefresh）时刷新
+    // 未读数：进工作区、切页面、或通知页标了已读（unreadRefresh）时刷新；
+    // 停留不动时每 30 秒再拉一次，这样"任务被指派/快到期/已逾期"不用切页面也能看到角标。
     LaunchedEffect(current?.id, tab, unreadRefresh) {
         val ws = current ?: return@LaunchedEffect
-        unread = api.unreadCount(ws.id)
+        while (true) {
+            unread = api.unreadCount(ws.id)
+            delay(30_000)
+        }
     }
 
     // 版本检查：登录成功后查一次就够，查不到（网络、没发布过包）就当没有新版
@@ -234,11 +239,15 @@ private fun AppRoot(joinUri: String?) {
                         WorkspaceTab.Notifications -> NotificationsScreen(
                             api = api,
                             workspaceId = ws.id,
-                            onOpenItem = { itemId, isTicket ->
-                                // 通知点开后跳到对应列表并展开那一条；通知本身不带数据，页面自己回源
+                            onOpenItem = { itemId, itemKind ->
+                                // 通知点开后跳到对应页签并展开那一条；通知本身不带数据，页面自己回源
                                 reopenItem = itemId
-                                reopenKnowledge = false
-                                tab = if (isTicket) WorkspaceTab.Tickets else WorkspaceTab.Tasks
+                                reopenKnowledge = itemKind == "knowledge"
+                                tab = when (itemKind) {
+                                    "knowledge" -> WorkspaceTab.Knowledge
+                                    "ticket" -> WorkspaceTab.Tickets
+                                    else -> WorkspaceTab.Tasks
+                                }
                             },
                             onUnreadChanged = { unreadRefresh += 1 },
                         )

android/app/src/main/java/com/dadao/task/data/Api.kt

@@ -328,6 +328,8 @@ data class AppNotification(
     val id: String,
     val kind: String = "",
     @SerialName("item_id") val itemId: String? = null,
+    /** task / ticket / knowledge：决定点开跳到哪个页签。 */
+    @SerialName("item_kind") val itemKind: String? = null,
     @SerialName("item_title") val itemTitle: String? = null,
     val title: String = "",
     val body: String = "",

android/app/src/main/java/com/dadao/task/ui/NotificationsScreen.kt

@@ -32,6 +32,7 @@ import androidx.compose.ui.unit.sp
 import com.dadao.task.data.Api
 import com.dadao.task.data.ApiException
 import com.dadao.task.data.AppNotification
+import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
 
 /**
@@ -44,7 +45,7 @@ import kotlinx.coroutines.launch
 fun NotificationsScreen(
     api: Api,
     workspaceId: String,
-    onOpenItem: (itemId: String, isTicket: Boolean) -> Unit,
+    onOpenItem: (itemId: String, itemKind: String) -> Unit,
     onUnreadChanged: () -> Unit,
     refreshKey: Int = 0,
 ) {
@@ -54,17 +55,25 @@ fun NotificationsScreen(
     var error by remember { mutableStateOf<String?>(null) }
     val scope = rememberCoroutineScope()
 
-    suspend fun reload() {
-        loading = true
+    suspend fun reload(silent: Boolean = false) {
+        if (!silent) loading = true
         error = null
         runCatching { api.notifications(workspaceId, unreadOnly) }
             .onSuccess { rows = it.notifications }
             .onFailure { error = verifyStatusCode((it as? ApiException)?.code ?: 0) }
-        loading = false
+        if (!silent) loading = false
     }
 
     LaunchedEffect(workspaceId, unreadOnly, refreshKey) { reload() }
 
+    // 停在通知页时也要能看到新动静：每 30 秒静默拉一次，不闪加载态。
+    LaunchedEffect(workspaceId, unreadOnly) {
+        while (true) {
+            delay(30_000)
+            reload(silent = true)
+        }
+    }
+
     Column(Modifier.fillMaxSize().padding(horizontal = 16.dp)) {
         Row(
             modifier = Modifier.fillMaxWidth(),
@@ -85,6 +94,26 @@ fun NotificationsScreen(
                 bg = if (unreadOnly) PaperSunken else PrimarySoft,
                 modifier = Modifier.clickable { unreadOnly = false },
             )
+            Box(Modifier.weight(1f))
+            SoftPill(
+                text = "刷新",
+                fg = InkMuted,
+                bg = PaperSunken,
+                modifier = Modifier.clickable { scope.launch { reload() } },
+            )
+            SoftPill(
+                text = "全部已读",
+                fg = InkMuted,
+                bg = PaperSunken,
+                modifier = Modifier.clickable {
+                    scope.launch {
+                        runCatching { api.markAllNotificationsRead(workspaceId) }
+                        rows = rows.map { if (it.readAt == null) it.copy(readAt = "read") else it }
+                        onUnreadChanged()
+                        reload(silent = true)
+                    }
+                },
+            )
         }
 
         Text(
@@ -121,7 +150,14 @@ fun NotificationsScreen(
             contentPadding = androidx.compose.foundation.layout.PaddingValues(bottom = 20.dp),
         ) {
             items(rows, key = { it.id }) { n ->
-                val isTicket = n.kind.startsWith("ticket_")
+                // 知识/工单/任务三种落点：优先看后端给的 item_kind，老数据再退回 kind 前缀
+                val isKnowledge = n.kind.startsWith("knowledge_") || n.itemKind == "knowledge"
+                val isTicket = !isKnowledge && (n.kind.startsWith("ticket_") || n.itemKind == "ticket")
+                val targetKind = when {
+                    isKnowledge -> "knowledge"
+                    isTicket -> "ticket"
+                    else -> "task"
+                }
                 SoftCard(
                     Modifier.fillMaxWidth(),
                     onClick = {
@@ -131,7 +167,7 @@ fun NotificationsScreen(
                                 rows = rows.map { if (it.id == n.id) it.copy(readAt = "read") else it }
                                 onUnreadChanged()
                             }
-                            n.itemId?.let { onOpenItem(it, isTicket) }
+                            n.itemId?.let { onOpenItem(it, targetKind) }
                         }
                     },
                 ) {
@@ -143,7 +179,11 @@ fun NotificationsScreen(
                             contentAlignment = Alignment.Center,
                         ) {
                             Text(
-                                text = if (isTicket) "工" else "记",
+                                text = when {
+                                    isKnowledge -> "知"
+                                    isTicket -> "工"
+                                    else -> "记"
+                                },
                                 fontSize = 11.sp,
                                 fontWeight = FontWeight.SemiBold,
                                 color = if (n.readAt == null) Primary else InkMuted,

backend/alembic/versions/0017_notification_reminders.py

@@ -0,0 +1,60 @@
+"""通知提醒：幂等键 + 到期扫描的只读口子
+
+Revision ID: 0017
+Revises: 0016
+Create Date: 2026-11-10
+
+两件事：
+
+1. **提醒的幂等键**。到期/逾期提醒由后台循环每几分钟扫一次，扫描本身有
+   advisory lock 保证只有一个进程在跑，但进程重启、时钟抖动、人工重跑都可能
+   让同一条提醒再写一次。`dedupe_key` + 部分唯一索引把"同一件事只提醒一次"
+   交给数据库保证，调用方用 `ON CONFLICT DO NOTHING` 即可。普通通知的
+   `dedupe_key` 为空，不参与唯一约束。
+
+2. **到期扫描要跨租户列出待办**。提醒是平台级定时任务，扫的时候没有"当前工作区"，
+   `item` 的隔离策略会让它一行都看不到。这里照 0016 的做法加一条只在
+   `app.reminder_list = 'on'` 时生效的 **SELECT-only** 策略：扫描器能列出
+   全平台的截止时间，但写通知仍然必须逐个工作区绑定租户，改不了别人的数据。
+"""
+
+from __future__ import annotations
+
+from collections.abc import Sequence
+
+import sqlalchemy as sa
+from alembic import op
+
+from app.roles import APP_ROLE
+
+revision: str = "0017"
+down_revision: str = "0016"
+branch_labels: Sequence[str] | None = None
+depends_on: Sequence[str] | None = None
+
+CREATE_REMINDER_POLICY = """
+CREATE POLICY item_reminder_list ON item
+    FOR SELECT
+    USING (current_setting('app.reminder_list', true) = 'on')
+"""
+
+
+def upgrade() -> None:
+    op.add_column("notification", sa.Column("dedupe_key", sa.String(120), nullable=True))
+    op.create_index(
+        "uq_notification_dedupe",
+        "notification",
+        ["workspace_id", "user_id", "dedupe_key"],
+        unique=True,
+        postgresql_where=sa.text("dedupe_key IS NOT NULL"),
+    )
+
+    op.execute("DROP POLICY IF EXISTS item_reminder_list ON item")
+    op.execute(CREATE_REMINDER_POLICY)
+    op.execute(f"GRANT SELECT ON item TO {APP_ROLE}")
+
+
+def downgrade() -> None:
+    op.execute("DROP POLICY IF EXISTS item_reminder_list ON item")
+    op.drop_index("uq_notification_dedupe", table_name="notification")
+    op.drop_column("notification", "dedupe_key")

backend/app/api/items.py

@@ -205,6 +205,48 @@ async def _apply_update(
     return item
 
 
+async def _notify_status_change(
+    session: AsyncSession,
+    *,
+    ws_id: uuid.UUID,
+    item: Item,
+    previous: str,
+    to_status: str,
+    actor_id: uuid.UUID,
+    actor_name: str,
+) -> None:
+    """状态变化的通知。
+
+    "完成"单独一种 kind：收件人一眼能看出是结项，而不是又一次普通的状态流转；
+    其余状态仍走 `task_status_changed`，正文里写清从什么改成了什么。
+    """
+    if to_status == "done":
+        await notify(
+            session,
+            ws_id=ws_id,
+            user_ids=(item.creator_id, item.assignee_id),
+            kind="task_completed",
+            item_id=item.id,
+            title=f"「{item.title}」已完成",
+            body=f"{actor_name} 把它标记为完成。",
+            actor_id=actor_id,
+        )
+        return
+    await notify(
+        session,
+        ws_id=ws_id,
+        user_ids=(item.creator_id, item.assignee_id),
+        kind="task_status_changed",
+        item_id=item.id,
+        title=f"「{item.title}」变成{TASK_STATUS_CN.get(to_status, to_status)}了",
+        body=(
+            f"{actor_name} 把它从 {TASK_STATUS_CN.get(previous, previous)} "
+            f"改成了 {TASK_STATUS_CN.get(to_status, to_status)}"
+        ),
+        actor_id=actor_id,
+    )
+
+
 # ── 列表 ────────────────────────────────────────────────────────────────
 def _apply_filters(
     stmt: Select,
@@ -581,6 +623,17 @@ async def batch_status(body: BatchStatusIn, ctx: MemberDep, session: SessionDep)
                 }
             )
             continue
+        # 批量改状态以前是"悄悄改完"：被指派人/创建人收不到任何通知，
+        # 和单条改状态的行为不一致。这里补上同一条通知。
+        await _notify_status_change(
+            session,
+            ws_id=ctx.ws_id,
+            item=item,
+            previous=previous,
+            to_status=body.status,
+            actor_id=ctx.user.id,
+            actor_name=ctx.user.nickname or "同事",
+        )
         updated.append({"id": str(item.id), "version": item.version, "unchanged": False})
 
     return ok(
@@ -682,19 +735,14 @@ async def change_status(
         payload={"from": previous, "to": body.status},
     )
     tags = await _tags_of(session, ctx.ws_id, [item.id])
-    await notify(
+    await _notify_status_change(
         session,
         ws_id=ctx.ws_id,
-        user_ids=(item.creator_id, item.assignee_id),
-        kind="task_status_changed",
-        item_id=item.id,
-        title=f"「{item.title}」变成{TASK_STATUS_CN.get(body.status, body.status)}了",
-        body=(
-            f"{ctx.user.nickname or '同事'} 把它从 "
-            f"{TASK_STATUS_CN.get(previous, previous)} 改成了 "
-            f"{TASK_STATUS_CN.get(body.status, body.status)}"
-        ),
+        item=item,
+        previous=previous,
+        to_status=body.status,
         actor_id=ctx.user.id,
+        actor_name=ctx.user.nickname or "同事",
     )
     return ok(_item_out(item, tags.get(item.id)), message="状态已更新")
 

backend/app/api/knowledge.py

@@ -45,6 +45,7 @@ from ..schemas import clamp_limit, decode_cursor, encode_cursor, ok
 from ..serializers import item_out, tags_of
 from ..services.knowledge import create_draft_from_source, find_doc_by_source
 from ..services.knowledge_index import reindex_document, search_knowledge
+from ..services.notify import notify, workspace_admins
 from .attachments import count_for_items, list_for_item
 
 router = APIRouter(prefix="/workspaces/{ws_id}", tags=["知识库"])
@@ -1025,6 +1026,17 @@ async def create_knowledge(body: KnowledgeIn, ctx: MemberDep, session: SessionDe
     await session.flush()
     await _log(session, item, ctx.user.id, "knowledge_created", {"generated_by": "human"})
     await _set_tags_for(session, ws_id, item, body.tag_names)
+    # 知识是团队资产：新建草稿先告诉能发布的人，别让草稿在列表里躺到没人发现。
+    await notify(
+        session,
+        ws_id=ws_id,
+        user_ids=await workspace_admins(session, ws_id),
+        kind="knowledge_draft_created",
+        item_id=item.id,
+        title=f"新的知识草稿：{item.title}",
+        body=f"{ctx.user.nickname or '同事'} 新建了一条知识，核对后可以发布。",
+        actor_id=ctx.user.id,
+    )
     await audit_record(
         session,
         workspace_id=ws_id,
@@ -1204,6 +1216,42 @@ async def change_status(
         target_id=str(item.id),
         payload={"to": to_status},
     )
+    # 知识的状态变化要让相关的人知道：提交审议找管理员核对，
+    # 发布/归档则回告作者——否则作者不知道自己的草稿已经被团队采纳。
+    actor_name = ctx.user.nickname or "同事"
+    if body.action == "submit_review":
+        await notify(
+            session,
+            ws_id=ws_id,
+            user_ids=await workspace_admins(session, ws_id),
+            kind="knowledge_review_requested",
+            item_id=item.id,
+            title=f"待核对：{item.title}",
+            body=f"{actor_name} 提交了一份知识，核对后可以发布。",
+            actor_id=ctx.user.id,
+        )
+    elif body.action == "publish":
+        await notify(
+            session,
+            ws_id=ws_id,
+            user_ids=(doc.author_id,),
+            kind="knowledge_published",
+            item_id=item.id,
+            title=f"「{item.title}」已发布",
+            body=f"{actor_name} 发布了这份知识，现在可以被团队检索到。",
+            actor_id=ctx.user.id,
+        )
+    elif body.action == "archive":
+        await notify(
+            session,
+            ws_id=ws_id,
+            user_ids=(doc.author_id,),
+            kind="knowledge_archived",
+            item_id=item.id,
+            title=f"「{item.title}」已归档",
+            body=f"{actor_name} 把它归档了，检索不再返回它。",
+            actor_id=ctx.user.id,
+        )
     await session.flush()
     if body.action == "publish":
         # 发布后立刻建索引：检索只认 published，不在这里建就要等定时任务，
@@ -1270,6 +1318,16 @@ async def promote_to_knowledge(
     await _log(
         session, doc_item, ctx.user.id, "knowledge_created", {"source_item_id": str(source.id)}
     )
+    await notify(
+        session,
+        ws_id=ws_id,
+        user_ids=await workspace_admins(session, ws_id),
+        kind="knowledge_draft_created",
+        item_id=doc_item.id,
+        title=f"从事项沉淀了知识：{doc_item.title}",
+        body=f"{ctx.user.nickname or '同事'} 把「{source.title}」沉淀成草稿，核对后可以发布。",
+        actor_id=ctx.user.id,
+    )
     await audit_record(
         session,
         workspace_id=ws_id,

backend/app/api/tickets.py

@@ -767,11 +767,14 @@ async def delete_link(
 
 
 # -- 通知 ---------------------------------------------------------------
-def _notification_out(n: Notification, item_title: str | None = None) -> dict[str, Any]:
+def _notification_out(
+    n: Notification, item_title: str | None = None, item_kind: str | None = None
+) -> dict[str, Any]:
     return {
         "id": str(n.id),
         "kind": n.kind,
         "item_id": str(n.item_id) if n.item_id else None,
+        "item_kind": item_kind,
         "item_title": item_title,
         "title": n.title,
         "body": n.body,
@@ -813,18 +816,27 @@ async def list_notifications(
     rows = list(rows[:limit])
 
     titles: dict[uuid.UUID, str] = {}
+    kinds: dict[uuid.UUID, str] = {}
     item_ids = [n.item_id for n in rows if n.item_id]
     if item_ids:
-        for item_id, title in (
-            await session.execute(select(Item.id, Item.title).where(Item.id.in_(item_ids)))
+        for item_id, title, kind in (
+            await session.execute(
+                select(Item.id, Item.title, Item.kind).where(Item.id.in_(item_ids))
+            )
         ).all():
             titles[item_id] = title
+            kinds[item_id] = kind
 
     next_cursor = encode_cursor(rows[-1].created_at, rows[-1].id) if has_more and rows else None
     return ok(
         {
             "notifications": [
-                _notification_out(n, titles.get(n.item_id) if n.item_id else None) for n in rows
+                _notification_out(
+                    n,
+                    titles.get(n.item_id) if n.item_id else None,
+                    kinds.get(n.item_id) if n.item_id else None,
+                )
+                for n in rows
             ],
             "next_cursor": next_cursor,
             "has_more": has_more,

backend/app/config.py

@@ -112,6 +112,14 @@ class Settings(BaseSettings):
     # 30 分钟够一次阅读/编辑，过期后刷新页面会重新签发。
     attachment_url_ttl_seconds: int = 1800
 
+    # ── 站内提醒 ──────────────────────────────────────────
+    # 到期/逾期提醒是后台轮询，不引入额外组件（见 services/reminders.py）。
+    # 间隔决定"最晚多久能收到提醒"，5 分钟对截止时间以小时计的任务足够。
+    reminders_enabled: bool = True
+    reminder_interval_seconds: int = 300
+    # 提前多久提醒"快到期"。默认 24 小时；改成 0 等于只提醒逾期。
+    reminder_due_soon_hours: int = 24
+
     # ── 知识检索（M3）──────────────────────────────────────
     # 切片大小与重叠：中文一段 600 字大约 400~600 token，够表达一个完整片段；
     # 重叠 80 字是为了不把跨段的话切断（检索命中时前后文还读得懂）。

backend/app/main.py

@@ -32,6 +32,7 @@ from .db import SessionFactory, current_app_role, engine
 from .errors import AppError, ErrorCode, http_status_for
 from .logging_setup import get_logger, request_id_ctx, setup_logging
 from .middleware import IdempotencyMiddleware, RequestContextMiddleware, error_body
+from .services import reminders
 from .services.wechat_bot import manager as wechat_manager
 
 settings = get_settings()
@@ -53,7 +54,10 @@ async def lifespan(app: FastAPI):
     )
     # 已登录的微信通道在进程启动时接上，不然重启之后消息就静默收不到了。
     await wechat_manager.start_all()
+    # 到期/逾期提醒：多 worker 下靠 advisory lock 保证只有一个进程在扫。
+    reminders.start()
     yield
+    await reminders.shutdown()
     await wechat_manager.shutdown()
     await engine.dispose()
 

backend/app/models_ticket.py

@@ -26,6 +26,7 @@ from sqlalchemy import (
     Text,
     UniqueConstraint,
     func,
+    text,
 )
 from sqlalchemy.dialects.postgresql import UUID as PgUUID
 from sqlalchemy.orm import Mapped, mapped_column
@@ -121,6 +122,16 @@ class Notification(Base, Timestamps):
     __table_args__ = (
         Index("ix_notification_ws_user_read", "workspace_id", "user_id", "read_at"),
         Index("ix_notification_ws_created", "workspace_id", "created_at"),
+        # 到期/逾期提醒由后台循环生成，可能被重复触发；带 dedupe_key 的写入用
+        # ON CONFLICT DO NOTHING，把"同一件事只提醒一次"交给数据库保证。
+        Index(
+            "uq_notification_dedupe",
+            "workspace_id",
+            "user_id",
+            "dedupe_key",
+            unique=True,
+            postgresql_where=text("dedupe_key IS NOT NULL"),
+        ),
     )
 
     id: Mapped[uuid.UUID] = mapped_column(PgUUID(as_uuid=True), primary_key=True, default=new_uuid)
@@ -137,6 +148,9 @@ class Notification(Base, Timestamps):
     title: Mapped[str] = mapped_column(String(120), nullable=False)
     body: Mapped[str] = mapped_column(String(300), nullable=False, default="")
     read_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
+    # 提醒类通知的幂等键（如 task_due_soon:<item>:<due_at>）。
+    # 普通通知为空，不参与唯一约束。
+    dedupe_key: Mapped[str | None] = mapped_column(String(120))
     created_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), nullable=False, server_default=func.now()
     )

backend/app/services/notify.py

@@ -15,8 +15,11 @@ from __future__ import annotations
 import uuid
 from collections.abc import Iterable
 
+from sqlalchemy import select
+from sqlalchemy.dialects.postgresql import insert as pg_insert
 from sqlalchemy.ext.asyncio import AsyncSession
 
+from ..models import Member
 from ..models_ticket import Notification
 
 TICKET_STATUS_CN = {
@@ -48,6 +51,7 @@ async def notify(
     title: str,
     body: str = "",
     actor_id: uuid.UUID | None = None,
+    dedupe_key: str | None = None,
 ) -> int:
     """给若干人各写一条通知，返回实际写入条数。
 
@@ -67,7 +71,55 @@ async def notify(
                 item_id=item_id,
                 title=title[:120],
                 body=body[:300],
+                dedupe_key=dedupe_key,
             )
         )
         count += 1
     return count
+
+
+async def notify_once(
+    session: AsyncSession,
+    *,
+    ws_id: uuid.UUID,
+    user_id: uuid.UUID | None,
+    kind: str,
+    item_id: uuid.UUID | None,
+    title: str,
+    body: str = "",
+    dedupe_key: str,
+    actor_id: uuid.UUID | None = None,
+) -> bool:
+    """写一条带幂等键的通知；已经写过就跳过，返回是否真的写入。
+
+    后台提醒循环会反复扫同一批任务，靠 `dedupe_key` 的唯一索引把重复挡在数据库层，
+    比"先查再插"少一次竞态。提醒本身不是业务事实，丢了不致命，重复才烦人。
+    """
+    if user_id is None or user_id == actor_id:
+        return False
+    result = await session.execute(
+        pg_insert(Notification)
+        .values(
+            workspace_id=ws_id,
+            user_id=user_id,
+            kind=kind,
+            item_id=item_id,
+            title=title[:120],
+            body=body[:300],
+            dedupe_key=dedupe_key,
+        )
+        .on_conflict_do_nothing()
+    )
+    return result.rowcount > 0
+
+
+async def workspace_admins(session: AsyncSession, ws_id: uuid.UUID) -> list[uuid.UUID]:
+    """工作区里能"发布/把关"的人：owner + admin，只算正常成员。"""
+    rows = await session.execute(
+        select(Member.user_id).where(
+            Member.workspace_id == ws_id,
+            Member.status == "active",
+            Member.role.in_(("owner", "admin")),
+        )
+    )
+    return [row[0] for row in rows]

backend/app/services/reminders.py

@@ -0,0 +1,215 @@
+"""到期与逾期提醒。
+
+为什么是"轮询 + 数据库租约"而不是引入 Celery/APScheduler：
+
+1. 生产是 gunicorn 多 worker，进程内定时器会各跑一遍，通知就重复了。
+   `pg_try_advisory_lock` 是现成的单实例租约，和微信机器人用的是同一套做法，
+   不额外增加运维组件。
+2. 提醒的准确度要求是"几分钟内"，不是秒级；一轮扫描就是一条按
+   `(workspace_id, status, due_at)` 索引的查询，代价可以忽略。
+3. 重复触发用 `notification.dedupe_key` 兜底：扫描器重启、时钟抖动、
+   人工补跑都不会把同一条提醒写两遍。
+
+扫描本身跨租户（平台级任务），所以先在 `app.reminder_list = 'on'` 的只读口子下
+把候选任务列出来，再逐个工作区绑定租户写通知——读可以跨，写必须归位。
+"""
+
+from __future__ import annotations
+
+import asyncio
+import math
+import uuid
+from contextlib import suppress
+from datetime import datetime, timedelta, timezone
+from typing import Any
+from zoneinfo import ZoneInfo
+
+from sqlalchemy import select, text
+
+from ..config import get_settings
+from ..db import SessionFactory, bind_tenant, engine
+from ..logging_setup import get_logger
+from ..models_task import Item
+from .notify import notify_once
+
+logger = get_logger("app.reminders")
+
+_LOCK_NAMESPACE = "dadao.reminders"
+# 一轮最多处理这么多条：正常量级远小于它；真到了这个量级，说明该拆任务而不是加锁。
+_SCAN_LIMIT = 500
+
+_task: asyncio.Task[None] | None = None
+_stopping = asyncio.Event()
+
+
+async def _candidates() -> list[dict[str, Any]]:
+    """列出所有"还没完成、有截止时间、已经进入提醒窗口"的事项。"""
+    settings = get_settings()
+    now = datetime.now(timezone.utc)
+    horizon = now + timedelta(hours=max(1, settings.reminder_due_soon_hours))
+    async with SessionFactory() as session:
+        await session.execute(text("SELECT set_config('app.reminder_list', 'on', true)"))
+        rows = (
+            await session.execute(
+                select(
+                    Item.id,
+                    Item.workspace_id,
+                    Item.title,
+                    Item.status,
+                    Item.due_at,
+                    Item.creator_id,
+                    Item.assignee_id,
+                )
+                .where(
+                    Item.deleted_at.is_(None),
+                    Item.kind != "knowledge",
+                    Item.status.not_in(("done", "canceled")),
+                    Item.due_at.is_not(None),
+                    Item.due_at <= horizon,
+                )
+                .order_by(Item.due_at)
+                .limit(_SCAN_LIMIT)
+            )
+        ).all()
+    return [dict(row._mapping) for row in rows]
+
+
+def _local(dt: datetime) -> datetime:
+    return dt.astimezone(ZoneInfo(get_settings().default_timezone))
+
+
+def _due_soon_message(row: dict[str, Any], now: datetime) -> tuple[str, str]:
+    due_at = row["due_at"]
+    hours = max(1, math.ceil((due_at - now).total_seconds() / 3600))
+    return (
+        f"「{row['title']}」{hours} 小时内到期",
+        f"截止时间 {_local(due_at):%m-%d %H:%M}，请尽快处理。",
+    )
+
+
+def _overdue_message(row: dict[str, Any], now: datetime) -> tuple[str, str]:
+    due_at = row["due_at"]
+    late = now - due_at
+    days = late.days
+    if days >= 1:
+        tail = f"已经逾期 {days} 天"
+    else:
+        tail = f"已经逾期 {max(1, int(late.total_seconds() // 3600))} 小时"
+    return (
+        f"「{row['title']}」已逾期",
+        f"原定 {_local(due_at):%m-%d %H:%M} 完成，{tail}。",
+    )
+
+
+async def _remind_workspace(ws_id: uuid.UUID, rows: list[dict[str, Any]], now: datetime) -> int:
+    sent = 0
+    async with SessionFactory() as session, session.begin():
+        await bind_tenant(session, ws_id, None)
+        for row in rows:
+            recipient = row["assignee_id"] or row["creator_id"]
+            if recipient is None:
+                continue
+            due_at: datetime = row["due_at"]
+            if due_at > now:
+                title, body = _due_soon_message(row, now)
+                kind = "task_due_soon"
+                dedupe = f"task_due_soon:{row['id']}:{due_at.isoformat()}"
+            else:
+                title, body = _overdue_message(row, now)
+                kind = "task_overdue"
+                today = _local(now).date().isoformat()
+                dedupe = f"task_overdue:{row['id']}:{due_at.isoformat()}:{today}"
+            if await notify_once(
+                session,
+                ws_id=ws_id,
+                user_id=recipient,
+                kind=kind,
+                item_id=row["id"],
+                title=title,
+                body=body,
+                dedupe_key=dedupe,
+            ):
+                sent += 1
+    return sent
+
+
+async def tick() -> dict[str, int]:
+    """扫一轮。返回本轮的统计，供日志与测试使用。"""
+    settings = get_settings()
+    if not settings.reminders_enabled:
+        return {"scanned": 0, "sent": 0, "skipped": 1}
+
+    lock_conn = await engine.connect()
+    try:
+        got = (
+            await lock_conn.execute(
+                text("SELECT pg_try_advisory_lock(hashtext(:ns))"), {"ns": _LOCK_NAMESPACE}
+            )
+        ).scalar()
+        if not got:
+            # 另一个 worker 正在扫，这一轮让给它。
+            return {"scanned": 0, "sent": 0, "skipped": 1}
+
+        now = datetime.now(timezone.utc)
+        rows = await _candidates()
+        by_ws: dict[uuid.UUID, list[dict[str, Any]]] = {}
+        for row in rows:
+            by_ws.setdefault(row["workspace_id"], []).append(row)
+
+        sent = 0
+        for ws_id, group in by_ws.items():
+            sent += await _remind_workspace(ws_id, group, now)
+        if sent:
+            logger.info(
+                "到期提醒已发送",
+                extra={"extra_fields": {"scanned": len(rows), "sent": sent}},
+            )
+        return {"scanned": len(rows), "sent": sent, "skipped": 0}
+    finally:
+        # session 级 advisory lock 挂在连接上；解锁后连接才能安全回到池里。
+        # 连接已断时解锁失败无需处理，连接本身也回不了池。
+        with suppress(Exception):
+            await lock_conn.execute(
+                text("SELECT pg_advisory_unlock(hashtext(:ns))"), {"ns": _LOCK_NAMESPACE}
+            )
+        await lock_conn.close()
+
+
+async def _loop() -> None:
+    settings = get_settings()
+    while not _stopping.is_set():
+        try:
+            await tick()
+        except asyncio.CancelledError:
+            raise
+        except Exception:  # pragma: no cover - 单轮失败不该把循环打死
+            logger.exception("到期提醒扫描失败")
+        try:
+            await asyncio.wait_for(
+                _stopping.wait(), timeout=max(5, settings.reminder_interval_seconds)
+            )
+        except asyncio.TimeoutError:
+            continue
+
+
+def start() -> None:
+    """启动后台提醒循环。测试环境与关闭开关时直接不启动。"""
+    global _task
+    settings = get_settings()
+    if settings.env == "test" or not settings.reminders_enabled:
+        return
+    if _task is not None and not _task.done():
+        return
+    _stopping.clear()
+    _task = asyncio.create_task(_loop(), name="dadao-reminders")
+
+
+async def shutdown() -> None:
+    global _task
+    _stopping.set()
+    if _task is None:
+        return
+    _task.cancel()
+    with suppress(asyncio.CancelledError, Exception):
+        await _task
+    _task = None

backend/tests/test_notifications.py

@@ -11,11 +11,14 @@
 
 from __future__ import annotations
 
+from datetime import datetime, timedelta, timezone
 from typing import Any
 
 import pytest
 from httpx import AsyncClient
 
+from app.services import reminders
+
 from .conftest import create_workspace, login, unwrap
 
 V1 = "/api/v1"
@@ -269,3 +272,223 @@ async def test_unread_count_and_read_all(client: AsyncClient) -> None:
         )
     )
     assert count["unread"] == 0
+
+
+async def _set_status(
+    client: AsyncClient, user: dict[str, Any], ws_id: str, item: dict, status: str
+) -> dict:
+    return unwrap(
+        await client.post(
+            f"{V1}/workspaces/{ws_id}/items/{item['id']}/status",
+            json={"status": status, "version": item["version"]},
+            headers=user["headers"],
+        )
+    )
+
+
+@pytest.mark.asyncio
+async def test_task_completion_notifies_the_creator(client: AsyncClient) -> None:
+    """派出去的活被干完了，派活的人要知道——但干活的人不该收到"你完成了"。"""
+    owner = await login(client)
+    ws = await create_workspace(client, owner, "完成通知")
+    helper = await _member(client, owner, ws, "member")
+    item = await _task_assigned_to(client, owner, ws["id"], helper["user_id"], "季度盘点")
+
+    await _set_status(client, helper, ws["id"], item, "done")
+
+    owner_inbox = await _inbox(client, owner, ws["id"])
+    completed = [n for n in owner_inbox if n["kind"] == "task_completed"]
+    assert len(completed) == 1
+    assert completed[0]["item_id"] == item["id"]
+    assert completed[0]["item_kind"] == "task"
+    assert "已完成" in completed[0]["title"]
+    assert not [n for n in await _inbox(client, helper, ws["id"]) if n["kind"] == "task_completed"]
+
+
+@pytest.mark.asyncio
+async def test_batch_status_sends_the_same_notifications(client: AsyncClient) -> None:
+    """看板批量拖拽不能静默：拖 3 条完成，创建人就该收到 3 条完成通知。"""
+    owner = await login(client)
+    ws = await create_workspace(client, owner, "批量完成通知")
+    helper = await _member(client, owner, ws, "member")
+    items = [
+        await _task_assigned_to(client, owner, ws["id"], helper["user_id"], f"批量任务 {i}")
+        for i in range(3)
+    ]
+
+    unwrap(
+        await client.post(
+            f"{V1}/workspaces/{ws['id']}/items/batch-status",
+            json={
+                "status": "done",
+                "items": [{"id": item["id"], "version": item["version"]} for item in items],
+            },
+            headers=helper["headers"],
+        )
+    )
+
+    owner_inbox = await _inbox(client, owner, ws["id"])
+    completed = {n["item_id"] for n in owner_inbox if n["kind"] == "task_completed"}
+    assert completed == {item["id"] for item in items}
+    assert not [n for n in await _inbox(client, helper, ws["id"]) if n["kind"] == "task_completed"]
+
+
+@pytest.mark.asyncio
+async def test_knowledge_notifications_follow_the_flow(client: AsyncClient) -> None:
+    """知识库的四个节点都要有人知道：新草稿、待核对、已发布、已归档。"""
+    owner = await login(client)
+    ws = await create_workspace(client, owner, "知识通知")
+    admin = await _member(client, owner, ws, "admin")
+
+    doc = unwrap(
+        await client.post(
+            f"{V1}/workspaces/{ws['id']}/knowledge",
+            json={"title": "报价流程", "body_md": "先核价，再报给客户"},
+            headers=admin["headers"],
+        )
+    )
+
+    # 管理员新建草稿 → 其他管理员（owner）收到
+    created = [
+        n
+        for n in await _inbox(client, owner, ws["id"])
+        if n["kind"] == "knowledge_draft_created" and n["item_id"] == doc["id"]
+    ]
+    assert len(created) == 1
+    assert created[0]["item_kind"] == "knowledge"
+
+    # 提交核对 → owner 收到"待核对"
+    doc = unwrap(
+        await client.post(
+            f"{V1}/workspaces/{ws['id']}/knowledge/{doc['id']}/status",
+            json={"action": "submit_review", "version": doc["version"]},
+            headers=admin["headers"],
+        )
+    )
+    assert any(
+        n["kind"] == "knowledge_review_requested" and n["item_id"] == doc["id"]
+        for n in await _inbox(client, owner, ws["id"])
+    )
+
+    # 发布 → 作者（admin）收到
+    doc = unwrap(
+        await client.post(
+            f"{V1}/workspaces/{ws['id']}/knowledge/{doc['id']}/status",
+            json={"action": "publish", "version": doc["version"]},
+            headers=owner["headers"],
+        )
+    )
+    published = [
+        n
+        for n in await _inbox(client, admin, ws["id"])
+        if n["kind"] == "knowledge_published" and n["item_id"] == doc["id"]
+    ]
+    assert len(published) == 1
+    assert published[0]["item_kind"] == "knowledge"
+
+    # 归档 → 作者（admin）收到
+    unwrap(
+        await client.post(
+            f"{V1}/workspaces/{ws['id']}/knowledge/{doc['id']}/status",
+            json={"action": "archive", "version": doc["version"]},
+            headers=owner["headers"],
+        )
+    )
+    assert any(
+        n["kind"] == "knowledge_archived" and n["item_id"] == doc["id"]
+        for n in await _inbox(client, admin, ws["id"])
+    )
+
+
+async def _task_with_due(
+    client: AsyncClient,
+    owner: dict[str, Any],
+    ws_id: str,
+    assignee_id: str,
+    title: str,
+    due_at: datetime,
+    status: str = "todo",
+) -> dict:
+    return unwrap(
+        await client.post(
+            f"{V1}/workspaces/{ws_id}/items",
+            json={
+                "title": title,
+                "status": status,
+                "assignee_id": assignee_id,
+                "due_at": due_at.isoformat(),
+            },
+            headers=owner["headers"],
+        )
+    )
+
+
+@pytest.mark.asyncio
+async def test_reminders_cover_due_soon_and_overdue_once(client: AsyncClient) -> None:
+    """扫描器只负责"该提醒的人收到且只收到一次"，不负责业务判断。"""
+    owner = await login(client)
+    ws = await create_workspace(client, owner, "到期提醒")
+    helper = await _member(client, owner, ws, "member")
+    now = datetime.now(timezone.utc)
+
+    soon = await _task_with_due(
+        client, owner, ws["id"], helper["user_id"], "明早交付", now + timedelta(hours=3)
+    )
+    late = await _task_with_due(
+        client, owner, ws["id"], helper["user_id"], "昨天该交", now - timedelta(days=1)
+    )
+    await _task_with_due(
+        client,
+        owner,
+        ws["id"],
+        helper["user_id"],
+        "已经做完的",
+        now + timedelta(hours=1),
+        status="done",
+    )
+
+    first = await reminders.tick()
+    assert first["sent"] == 2, first
+
+    inbox = await _inbox(client, helper, ws["id"])
+    due_soon = [n for n in inbox if n["kind"] == "task_due_soon"]
+    overdue = [n for n in inbox if n["kind"] == "task_overdue"]
+    assert [n["item_id"] for n in due_soon] == [soon["id"]]
+    assert [n["item_id"] for n in overdue] == [late["id"]]
+    assert "截止时间" in due_soon[0]["body"]
+    assert "已逾期" in overdue[0]["title"]
+
+    # 第二轮不能重复写：dedupe_key 兜底
+    second = await reminders.tick()
+    assert second["sent"] == 0, second
+    inbox = await _inbox(client, helper, ws["id"])
+    assert len([n for n in inbox if n["kind"] == "task_due_soon"]) == 1
+    assert len([n for n in inbox if n["kind"] == "task_overdue"]) == 1
+
+
+@pytest.mark.asyncio
+async def test_reminders_stay_inside_each_workspace(client: AsyncClient) -> None:
+    """提醒是平台级扫描，但写通知必须回到各自工作区，不能串租户。"""
+    owner_a = await login(client)
+    ws_a = await create_workspace(client, owner_a, "提醒甲")
+    helper_a = await _member(client, owner_a, ws_a, "member")
+
+    owner_b = await login(client)
+    ws_b = await create_workspace(client, owner_b, "提醒乙")
+    helper_b = await _member(client, owner_b, ws_b, "member")
+
+    now = datetime.now(timezone.utc)
+    item_a = await _task_with_due(
+        client, owner_a, ws_a["id"], helper_a["user_id"], "甲的逾期", now - timedelta(hours=2)
+    )
+    item_b = await _task_with_due(
+        client, owner_b, ws_b["id"], helper_b["user_id"], "乙的逾期", now - timedelta(hours=2)
+    )
+
+    result = await reminders.tick()
+    assert result["sent"] == 2, result
+
+    inbox_a = await _inbox(client, helper_a, ws_a["id"])
+    inbox_b = await _inbox(client, helper_b, ws_b["id"])
+    assert {n["item_id"] for n in inbox_a if n["kind"] == "task_overdue"} == {item_a["id"]}
+    assert {n["item_id"] for n in inbox_b if n["kind"] == "task_overdue"} == {item_b["id"]}

web/src/lib/types.ts

@@ -224,6 +224,8 @@ export interface AppNotification {
   id: string;
   kind: string;
   item_id: string | null;
+  /** 事项类型：知识要跳阅读页，工单跳工单页，任务回任务页。 */
+  item_kind: "task" | "ticket" | "knowledge" | null;
   item_title: string | null;
   title: string;
   body: string;

web/src/pages/Notifications.tsx

@@ -2,21 +2,33 @@ import { useCallback, useEffect, useMemo, useState } from "react";
 import { useNavigate, useParams } from "react-router-dom";
 
 import { AppShell } from "../components/AppShell";
-import { Bell, Check, TicketIcon, Inbox, Clock } from "../components/icons";
+import { Bell, Book, Check, TicketIcon, Inbox, Clock, Flag } from "../components/icons";
 import { Button, EmptyState, PageHeader, SkeletonRows } from "../components/ui";
 import { api, ApiError } from "../lib/client";
 import type { AppNotification } from "../lib/types";
 
 const PAGE = 30;
 
-/** 工单类通知点开跳到工单页，其余回任务页——都带 `?open=`，落地即展开那一条。 */
+/**
+ * 点开跳到哪：知识走独立阅读页（整屏），工单去工单页，其余回任务页——
+ * 后两者都带 `?open=`，落地即展开那一条。判断以 `item_kind` 为准，
+ * 因为"知识被评论"的通知 kind 是 item_commented，光看 kind 会跳错页。
+ */
 function targetOf(wsId: string, n: AppNotification): string {
   if (!n.item_id) return `/w/${wsId}/notifications`;
-  const isTicket = n.kind.startsWith("ticket_");
-  return isTicket ? `/w/${wsId}/tickets?open=${n.item_id}` : `/w/${wsId}?open=${n.item_id}`;
+  if (n.item_kind === "knowledge" || n.kind.startsWith("knowledge_")) {
+    return `/w/${wsId}/knowledge/${n.item_id}`;
+  }
+  if (n.item_kind === "ticket" || n.kind.startsWith("ticket_")) {
+    return `/w/${wsId}/tickets?open=${n.item_id}`;
+  }
+  return `/w/${wsId}?open=${n.item_id}`;
 }
 
 function iconOf(kind: string) {
+  if (kind.startsWith("knowledge_")) return <Book size={15} />;
+  if (kind === "task_due_soon") return <Clock size={15} />;
+  if (kind === "task_overdue") return <Flag size={15} />;
   if (kind.startsWith("ticket_")) return <TicketIcon size={15} />;
   if (kind === "item_commented") return <Inbox size={15} />;
   return <Bell size={15} />;
@@ -113,7 +125,7 @@ export function NotificationsPage() {
       <PageHeader
         eyebrow="事情有动静时，这里会告诉你"
         title="通知"
-        desc="工单被接受、提交、验收，任务被指派、改状态，有人在你关注的事情下说话，都会落在这里。"
+        desc="任务被指派、完成、快到期或已逾期，工单被接受/验收，知识待核对/已发布，以及有人在你关注的事情下说话，都会落在这里。"
         actions={
           <>
             <Button variant="ghost" size="sm" onClick={() => void load(true)} disabled={loading}>